It is an important issue in pharmacy to deliver drugs at effective concentration to action sites with good stability and low toxicity. It can increase water solubility of a medicament by coupling the medicament to a water soluble polymer, such as polyethylene glycol (PEG). However, one shortcoming of the conventional PEG modification technique is that, in general, the medicament or other functional group could only link to two terminal ends of the PEG molecule, which remarkably limits the drug load capacity of the PEG carrier.
Therefore, it is still a problem to be solved of how to find a nontoxic carrier and administration method thereof which could increase water solubility and stability of the drug and reduce side effects of toxicity, and possess high drug load capacity. The present invention is directed to solving the problem.